Editing Interstate 45 (section)

==History==
In the initial assignment of state highways in 1917, the [[Dallas–Fort Worth metroplex]] and Greater Houston were connected by a branch of [[Texas State Highway 2|SH&nbsp;2]] ([[Meridian Highway]]), which ran via [[Waco, Texas|Waco]] and [[Bryan, Texas|Bryan]] and continued on to Galveston. The more direct route followed by I-45 was not initially part of the system between [[Richland, Texas|Richland]] and [[Huntsville, Texas|Huntsville]];<ref>{{cite news |work = [[Commerce Journal]] |title = Highway Commission Adopts 25 Highways |date = July 6, 1917 }}</ref><ref>{{cite map |author = Texas State Highway Department |url =  http://www.tsl.state.tx.us/cgi-bin/aris/maps/maplookup.php3?mapnum=6254 |title = Map Showing Proposed System of State Highways as Adopted June 1917 |archive-url = https://web.archive.org/web/20070310200319/http://www.tsl.state.tx.us/cgi-bin/aris/maps/maplookup.php3?mapnum=6254 |archive-date = March 10, 2007 }}{{full citation needed|date=April 2020}}</ref> this cutoff was added by 1919 as [[Texas State Highway 32 (pre-1939)|SH&nbsp;32]],<ref>{{cite map |author = Texas State Highway Department |url = http://www.tsl.state.tx.us/cgi-bin/aris/maps/maplookup.php3?mapnum=6183 |title = Highway Map: State of Texas |date = October 1, 1919 |archive-url = https://web.archive.org/web/20070310200355/http://www.tsl.state.tx.us/cgi-bin/aris/maps/maplookup.php3?mapnum=6183 |archive-date  = March 10, 2007 }}</ref> and [[U.S. Route 75 in Texas|US&nbsp;75]] was assigned to the alignment in 1926.<ref name="1926 map">{{cite map |author1= [[Bureau of Public Roads]] |author2= [[American Association of State Highway Officials]] |date= November 11, 1926 |title= United States System of Highways Adopted for Uniform Marking by the American Association of State Highway Officials |url= https://commons.wikimedia.org/wiki/File:United_States_System_of_Highways_Adopted_for_Uniform_Marking_by_the_American_Association_of_State_Highway_Officials.jpg |scale= 1:7,000,000 |location= Washington, DC |publisher= [[United States Geological Survey]] |oclc= 32889555 |access-date= November 7, 2013 |via= [[Wikimedia Commons]] |name-list-style= amp |archive-date= April 13, 2017 |archive-url= https://web.archive.org/web/20170413153913/https://commons.wikimedia.org/wiki/File:United_States_System_of_Highways_Adopted_for_Uniform_Marking_by_the_American_Association_of_State_Highway_Officials.jpg |url-status= live }}</ref> Prior to the coming of the [[Interstate Highway System]] in the late 1950s, the only improvements to US&nbsp;75 in Texas beyond building a two-lane paved roadway were in the Houston and Dallas areas.{{cn|date=October 2024}} The highways in and near these cities, however, included some of the first [[freeway]]s in the state: the Gulf Freeway (Houston) and the [[Central Expressway (Dallas)|Central Expressway]] (Dallas).

===Gulf Freeway (Houston to Galveston)===
{{Update|section|date=April 2020}}
The [[Galveston–Houston Electric Railway]] began operating an [[interurban]] between those cities on December 5, 1911, and last ran on October 31, 1936, though the [[Houston Electric Company]], operator of Houston's city transit system, continued to run trains on the portion between Downtown and [[Park Place, Houston|Park Place]]. A proposal for a "superhighway" between the cities was first made in 1930, and Houston Mayor [[Oscar F. Holcombe]] began to work toward it later that decade. He announced an agreement with the Houston Electric Company on April 12, 1940, through which the company could convert its four remaining lines to [[bus]]ses in exchange for the [[Right-of-way (property access)|right-of-way]] used by the Park Place line. This line was last used on June 9, 1940, the last day of streetcar service in Houston;<ref name=HF4>{{cite book |last = Slotboom |first = Erik |title = Houston Freeways: A Historical and Visual Journey |year = 2003 |publisher = Oscar F. "Erik" Slotboom |isbn = 0-9741605-3-9 |url = http://www.houstonfreeways.com/ |chapter = Chapter 4: The Spokes |access-date = September 11, 2006 |archive-url = https://web.archive.org/web/20060906040202/http://www.houstonfreeways.com/ |archive-date = September 6, 2006 |url-status = live }}{{sps|date=April 2020}}</ref> the replacement is still operated by the [[Houston Metro]] as the 40 along Telephone Road.

Before the new highway was built, [[U.S. Route 75 in Texas|US&nbsp;75]] followed Galveston Road (now mostly [[Texas State Highway 3|SH&nbsp;3]]), Broadway Street, and Harrisburg Boulevard into Downtown. [[Texas State Highway 225|SH&nbsp;225]] carried traffic from [[La Porte, Texas|La Porte]] along La Porte Road to US&nbsp;75 in [[Harrisburg, Houston|Harrisburg]], and [[Texas State Highway 35|SH&nbsp;35]] connected [[Alvin, Texas|Alvin]] with Downtown along Telephone Road and Leeland Street<!--earlier maps show Polk Street, but a 1939 TXDOT map confirms Leeland-->.{{cn|date=October 2024}} Plans made in October 1943, when the [[Texas Transportation Commission]] signed an agreement with Houston and [[Harris County, Texas|Harris County]], referred to the new bypass as a relocation of US&nbsp;75. Drawings were released by the state on January 31, 1946, and included almost continuous [[frontage road]]s, broken only at railroad crossings.<ref name=HF4/> Although the [[freeway]] ended at Live Oak Street, a so-called "four-street distribution system"<ref>{{cite book |author = [[Chamber of Commerce of the United States]] |title = Business Action for Better Cities |year = 1952 |publisher = Chamber of Commerce of the United States |page = 66 }}</ref> of four [[one-way street]]s, [[Signal timing|timed]] for {{convert|30|mph|km/h|abbr=on}}, carried traffic to Main Street.<ref>{{cite book |author = American Association of State Highway Officials |title = Proceedings: Convention Group Meetings, Papers and Discussions |location = Kansas City, Missouri |year = 1952 |publisher = American Association of State Highway Officials }}</ref> Initially, the two southwestern streets—Pierce Street and Calhoun Avenue (now St. Joseph Parkway)—carried traffic toward the freeway, and the other two—Jefferson and Pease streets—carried exiting traffic;<ref>{{cite web |publisher = Texas Department of Transportation archive library |url = http://www.texasfreeway.com/houston/historic/photos/images/gulf_freeway_1953.jpg |title = Aerial View of the Downtown End of the Gulf Freeway |archive-url = https://web.archive.org/web/20070927072343/http://www.texasfreeway.com/houston/historic/photos/images/gulf_freeway_1953.jpg |archive-date = September 27, 2007 |year = 1953 }}{{full citation needed|date=April 2020}}</ref> once the freeway was completed far enough to allow US&nbsp;75 to be marked along it, Pease and Pierce streets carried that highway to Fannin Street.{{cn|date=October 2024}}

The first freeway dedication in the state took place at 7:00&nbsp;pm on September 30, 1948, at the overpass over Calhoun Road by the [[University of Houston]]. The roadway between Downtown and Telephone Road<!--was SH 35 moved to the freeway?--> was opened to traffic after speeches but lacked an official name, being called the "Interurban Expressway", after the rail line that it replaced, by the press. Mayor Holcombe quickly started a contest to assign a name, and the city chose the winning entry on December 17, 1948. Sara Yancy of [[Houston Heights]] won $100 (equivalent to ${{Formatprice|{{Inflation|US|100|1948}}}} in {{Inflation/year|index=US}}{{Inflation/fn|index=US}}) for her submission of "Gulf Freeway", named for the [[Gulf of Mexico]] that the highway would reach when completed. The freeway was extended to Griggs Road in February 1951 and Reveille Street (onto which SH&nbsp;35 was realigned) in July 1951 and was completed to the [[Galveston Causeway]] on August 2, 1952, with a ceremony on the bridge over [[Farm to Market Road 517|FM&nbsp;517]] near [[Dickinson, Texas|Dickinson]]. However, beyond Reveille Street, the road was not built to [[freeway]] standards, with 32 [[at-grade intersection]]s, though no [[traffic signal]]s. The highway curved away from the old interurban right-of-way near Monroe Road, about where the Park Place streetcar line had ended. In December 1952, a short spur, now part of [[Interstate 610 (Texas)|I-610]], was opened to connect with SH&nbsp;225.<ref name=HF5>{{cite book |last = Slotboom |first = Erik |title = Houston Freeways: A Historical and Visual Journey |year = 2003 |publisher = Oscar F. "Erik" Slotboom |isbn = 0-9741605-3-9 |url = http://www.houstonfreeways.com/ |chapter = Chapter 5: The Loops |access-date = September 11, 2006 |archive-url = https://web.archive.org/web/20060906040202/http://www.houstonfreeways.com/ |archive-date = September 6, 2006 |url-status = live }}{{sps|date=April 2020}}</ref> A three-way split in the northwest part of Park Place, near where [[Gulfgate Shopping Center]] opened in 1956, carried nonstop traffic to and from SH&nbsp;35 and SH&nbsp;225.<ref name=HF4/><ref>{{cite web |publisher = Texas Department of Transportation Archive Library |url = http://www.texasfreeway.com/houston/historic/photos/images/i45_i610s_undated.jpg |title = Aerial View of the Gulfgate Shopping Center |archive-url = https://web.archive.org/web/20070927072259/http://www.texasfreeway.com/houston/historic/photos/images/i45_i610s_undated.jpg |archive-date = September 27, 2007 |date = c. 1960s }}</ref><ref name=NBI/> This split was also the location of a lane drop; the roadway carried six lanes (three in each direction) between Houston and the interchange and four beyond to Galveston. After the new US&nbsp;75 was completed, the old road between Downtown and [[South Houston, Texas|South Houston]] was dropped from the state highway system, while the remainder became SH&nbsp;3, connecting to the Gulf Freeway via Winkler Drive, effective August 20, 1952.<ref name=HDF-SH-3>{{TxDOT|SH|3|link=no}}</ref>

The first major change was made in preparation for the North Freeway connection, when the directions of Calhoun Avenue and Jefferson Street were swapped so that they would alternate. A bridge, dated 1954, was built to carry traffic from Jefferson Street over traffic to Jefferson Street,<ref name=NBI/> and US&nbsp;75 was moved to Calhoun Avenue northbound,<ref name=map-1955>{{cite map |author = [[General Drafting Company]] |url = http://www.texasfreeway.com/houston/historic/road_maps/images/1955_houston_humble_highres.jpg |title = Houston |archive-url = https://web.archive.org/web/20070927072241/http://www.texasfreeway.com/houston/historic/road_maps/images/1955_houston_humble_highres.jpg |archive-date = September 27, 2007 |year = 1955 |publisher = [[Humble Oil]] }}</ref> soon crossing downtown on the [[one-way pair]] of Calhoun Avenue and Pierce Street to the new North Freeway.<ref name=map-1958>{{cite map |author = General Drafting Company |url = http://www.texasfreeway.com/houston/historic/road_maps/images/1958_houston_humble_highres.jpg |title = Houston |archive-url = https://web.archive.org/web/20070929092744/http://www.texasfreeway.com/houston/historic/road_maps/images/1958_houston_humble_highres.jpg |archive-date = September 29, 2007  |year = 1958 |publisher = Humble Oil }}</ref> A [[median barrier]] was added in 1956 to prevent [[crossover accident]]s. Southeast of Downtown, the at-grade intersections proved dangerous, and only two<!--which two? is FM 1959 one?--> had been replaced with interchanges by 1959, when the [[Texas Highway Department]] began a program to upgrade the road to full [[freeway]] standards. [[Frontage road]]s would be required along the entire highway, since the state had not purchased access rights, and so abutting property owners were able to build driveways to the road. To accomplish this, traffic was shifted to the newly built frontage roads so that the central main lanes could be reconstructed. This grade separation was completed from Houston to Almeda-Genoa Road (exit&nbsp;34) in June 1959, [[Farm to Market Road 1959|FM&nbsp;1959]] (exit&nbsp;30) in October 1964, [[Farm to Market Road 518|FM&nbsp;518]] (exit&nbsp;23) in December 1970, and [[Farm to Market Road 1764|FM&nbsp;1764]] (exit&nbsp;15) in 1976. As the section beyond FM&nbsp;1764 into Galveston had already been rebuilt,<ref name=NBI/><ref>{{cite map |author = Texas State Highway Department |url = http://www.tsl.state.tx.us/cgi-bin/aris/maps/maplookup.php3?mapnum=5138 |title = General Highway Map: Galveston County, Texas |year = 1957 |orig-year = State highways revised to January 1, 1961 }}{{dead link|date=November 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><!--shows that the one at-grade on the map&nbsp;— Vauthier Road&nbsp;— was bypassed in 1961--> this marked the completion of the Gulf Freeway as an actual freeway.<ref name=HF4/>

[[Image:Houston, TX skyline from freeway.jpg|thumb|Looking northwest along the Gulf Freeway toward Downtown in 2006; the [[Texas State Highway Spur 5|Spur&nbsp;5]] distributor lanes, completed in 1988, are to the right]]
As the first freeway in Texas, the standards of the Gulf Freeway soon became inadequate, with poor sight lines and little room to merge when entering. It also attracted development, such as [[Gulfgate Center]], the first mall in the Houston area, the [[Manned Spacecraft Center]], and many [[residential development]]s. Heavy [[traffic congestion|congestion]] began to affect the freeway by the early 1960s; two roughly parallel freeways—the [[Harrisburg Freeway|Harrisburg]] and [[Alvin Freeway|Alvin]] freeways—were proposed at that time to relieve the traffic but were not built. A short project to widen the road to six lanes between I-610 and [[Sims Bayou]] was completed in 1960, and [[ramp meter]]s were installed in 1966. The I-610 interchange was rebuilt with direct connections for most movements in 1975. Plans to reconstruct the freeway near Downtown began in 1972, taking about 170&nbsp;houses and 22&nbsp;businesses from the southwest side for the room to expand the main lanes and add parallel lanes for the Alvin Freeway. Local opposition was unsuccessful at stopping the project, and construction on this segment, and others to the southeast, took place in the 1980s. The lanes were shifted outward to make room for the transitway, which opened to I-610 on May 16, 1988. These lanes were inspired by the similar ones on the [[Henry G. Shirley Memorial Highway]] in the [[Washington metropolitan area]].<ref name=HF6>{{cite book |last = Slotboom |first = Erik |title = Houston Freeways: A Historical and Visual Journey |year = 2003 |publisher = Oscar F. "Erik" Slotboom |isbn = 0-9741605-3-9 |url = http://www.houstonfreeways.com/ |chapter = Chapter 6: Freeway Mass Transit |access-date = September 11, 2006 |archive-url = https://web.archive.org/web/20060906040202/http://www.houstonfreeways.com/ |archive-date = September 6, 2006 |url-status = live }}{{sps|date=April 2020}}</ref> That year also marked the end of the reconstruction inside I-610, along with the elevated distribution lanes alongside the mainlanes near Downtown; the first short piece of the Alvin Freeway was finally connected to these in 1999. This project gave I-45 its current configuration, mostly eight mainlanes wide, from Sims Bayou past I-610 to Griggs Road in 1981, to Telephone Road in 1982, to Lockwood Drive in 1985, and, finally, to Downtown in 1988.<ref name=HF4/>

These projects, however, were not the end of construction on the Gulf Freeway. The highway beyond I-610 to FM&nbsp;1959, which had just been upgraded in the 1950s and 1960s, saw an extension of the transitway to a temporary end near FM&nbsp;1959, widening to eight lanes, and a large [[stack interchange]] at the [[Sam Houston Tollway]]. This reconstruction was completed between Almeda-Genoa Road and College Avenue in 1991, between College Avenue and Sims Bayou in 1994, and, finally in 1997, there was no construction anywhere on the entire length of the freeway when the tollway interchange was opened, along with the widening between Almeda-Genoa Road and FM&nbsp;1959. A 1999 study recommended widening the entire stretch from the Sam Houston Tollway to Galveston to at least eight lanes. Construction to replace the [[Galveston Causeway]] began in mid-2003,<ref name=HF4/> and work on a section through [[Webster, Texas|Webster]], including a new interchange with [[Texas State Highway NASA Road 1|NASA Road&nbsp;1]], began in mid-2007.<ref>{{cite press release |author = Texas Department of Transportation |url = http://www.dot.state.tx.us/news/local_news/houston_news/020-2007.htm |title = Reconstruction of IH 45—Gulf Freeway in Webster Announced |archive-url = https://web.archive.org/web/20121008212952/http://www.dot.state.tx.us/news/local_news/houston_news/020-2007.htm |archive-date = October 8, 2012  |date = June 11, 2007 }}{{full citation needed|date=April 2020}}</ref>

Widening of the freeway between Kurland Drive at Bay Area Boulevard began in July 2011. This construction will expand the number of freeway lanes from six to ten and increase the number of frontage lanes from four to six. The [[HOV lane]] will be extended to the southern end of the construction. It will also involve rebuilding the overpasses at Dixie Farm Road and Clear Lake City Boulevard. (Dixie Farm Road bridge demolition has already been completed.)<ref>{{cite news |url = http://www.yourhoustonnews.com/bay_area/news/article_e41c64f7-8092-57e1-87c7-68b70a8c267f.html |title = Gulf Freeway construction to begin this summer |first = Dana |last = Guthrie |work = Your Houston News |date = May 27, 2011 |access-date = June 29, 2011 |archive-url = https://web.archive.org/web/20110530150600/http://www.yourhoustonnews.com/bay_area/news/article_e41c64f7-8092-57e1-87c7-68b70a8c267f.html |archive-date = May 30, 2011 |url-status = live }}</ref> According to TxDOT, the project is approximately {{convert|15|mi|km}} in length, starting at Kurland and ending approximately {{convert|1|mi|km|spell=in}} south of Bay Area Boulevard.

The project has six phases. Phase one is the reconstruction of the mainlanes from the northern end of the project to just south of FM&nbsp;1959. The end of this phase will include the demolition and reconstruction of the bridge at the FM&nbsp;1959 intersection. Phase two, planned to begin in mid-2012, will be the reconstruction of the frontage roads from just south of FM&nbsp;1959 to the southern end of the project. Phase three will be the reconstruction of the mainlanes on the southern half of the project and is planned to begin in mid-2013. Phase four, scheduled to start late 2014, will be the demolition and reconstruction of the overpass at Clear Lake City Boulevard. Phase five (which was completed) was the demolition and reconstruction of El Dorado and Bay Area boulevards. The demolition and reconstruction was finished in 2016. As a result, the 1960s-era cloverleaf interchanges (with the exception of Fuqua Street and Scarsdale Boulevard) have been eliminated with overpasses. Phase six will be making the new lanes of the freeway. It will have five lanes each direction along with the new overpasses for those two underpasses. This will be completed 2017.

In 2015, reconstruction and widening of I-45 began in Downtown due to heavy traffic. The southbound onramp from Allen Parkway will be moved to enter on the right side, and long-range plans call for the demolition of the outdated Pierce Elevated, with the reroute of I-45 being along [[Interstate 69 in Texas|I-69]]/[[U.S. Route 59 in Texas|US&nbsp;59]] and [[Interstate 10 in Texas|I-10]]/[[U.S. Route 90 in Texas|US&nbsp;90]] to the North Freeway. The parts of the Gulf Freeway at I-10 and I-45 will be known as the Downtown Connector. If I-45 was rerouted and the Pierce Elevated demolished (and/or redeveloped into the proposed Pierce SkyPark as part of additional greenspace), the connecting ramps south of Allen Parkway would become a second downtown spur, which will result in the demise of a full freeway loop around Downtown. {{as of|2018}}, there are no plans to place the Pierce Elevated in a tunnel similar to Spur&nbsp;366 in Dallas since Greater Houston is prone to flooding, especially in the aftermath of [[Hurricane Harvey]].

===North Freeway (Houston to Conroe)===
[[File:North Freeway SB.JPG|thumb|Southbound on the North Freeway]]
The last alignment of US&nbsp;75 before the North Freeway was built left Downtown to the northwest on Main Street, turning north at Airline Drive, and then northwest along the present alignment of I-45, then known as Stuebner Airline Road, Shepherd Drive, and East Montgomery Road.<ref name=map-1955/> The freeway replacement was authorized in stages between May 1945 and June 1952, when the [[Texas Transportation Commission]] adopted plans for a freeway all the way between Houston and Dallas. The North Freeway name was adopted in 1956; an unsuccessful proposal in 1965 would have renamed it the Dallas Freeway.<ref name=HF1>{{cite book |last = Slotboom |first = Erik |title = Houston Freeways: A Historical and Visual Journey |year = 2003 |publisher = Oscar F. "Erik" Slotboom |isbn = 0-9741605-3-9 |url = http://www.houstonfreeways.com/ |chapter = Chapter 1: Building the System |access-date = September 11, 2006 |archive-url = https://web.archive.org/web/20060906040202/http://www.houstonfreeways.com/ |archive-date = September 6, 2006 |url-status = live }}{{sps|date=April 2020}}</ref> The first short piece of the freeway to open crossed [[Buffalo Bayou]], connecting the two [[one-way pair]]s from the north end of the Gulf Freeway with the south end of Houston Avenue. This section was opened on December 12, 1955, and allowed US&nbsp;75 to bypass its run on Main Street;<ref name=map-1958/> it included interchanges with [[Allen Parkway]] and [[Memorial Drive (Houston)|Memorial Drive]]. The next piece near downtown opened on July 24, 1962, leaving the 1955 freeway in the Allen Parkway interchange, passing east of Houston Avenue, and connected to an already-built portion at [[Interstate 610 (Texas)|I-610]]. The six-lane Pierce Elevated, which occupies half a block on the southwest side of Pierce Street, required the acquisition of a number of commercial properties; the cost prevented the full block from being used. This portion opened on August 18, 1967, connecting the Gulf and North Freeways and bypassing the "four-street distribution system", which remains in its original form to this day.<ref name=HF4/><ref name=HF3>{{cite book |last = Slotboom |first = Erik |title = Houston Freeways: A Historical and Visual Journey |year = 2003 |publisher = Oscar F. "Erik" Slotboom |isbn = 0-9741605-3-9 |url = http://www.houstonfreeways.com/ |chapter = Chapter 3: Downtown Freeways |access-date = September 11, 2006 |archive-url = https://web.archive.org/web/20060906040202/http://www.houstonfreeways.com/ |archive-date = September 6, 2006 |url-status = live }}{{sps|date=April 2020}}</ref>

The first piece of the North Freeway to be built outside I-610 was an upgrade of existing US&nbsp;75 on Stuebner Airline Road, between Airline and Shepherd drives, opened in December 1959. In April 1961, this was completed to the interchange with I-610, and, on July 24, 1962, the Downtown section was extended north to meet it. As each section opened, US&nbsp;75 was moved to it, temporarily using I-610 to Airline Drive for about a year.<ref>{{cite map |author = General Drafting Company |url = http://www.texasfreeway.com/houston/historic/road_maps/images/1961_houston_enco_highres.jpg |title = Houston, Texas |archive-url = https://web.archive.org/web/20070927072224/http://www.texasfreeway.com/houston/historic/road_maps/images/1961_houston_enco_highres.jpg |archive-date = September 27, 2007 |year  = 1961 |publisher = Humble Oil }}</ref><!--note that I-610 ended at Airline; with the current ramps you can't go from Airline to I-45 north via I-610--> At the other end, US&nbsp;75 was upgraded from [[Spring Creek (San Jacinto River tributary)|Spring Creek]] at the north edge of [[Spring, Texas|Spring]] north to the [[San Jacinto River (Texas)|San Jacinto River]] south of [[Conroe, Texas|Conroe]] in 1960.{{cn|date=October 2024}} In between, the upgrade was completed from [[Farm to Market Road 525|FM&nbsp;525]] to near Richey Road in December 1961, south to the 1959 segment in February 1963, and north to the 1960 segment in March 1963, completing the North Freeway except for the Pierce Elevated (1967). The freeway as initially built had eight lanes (four in each direction) between Downtown and I-610, six to [[Farm to Market Road 1960|FM&nbsp;1960]], and four north of FM&nbsp;1960.<ref name=HF4/>

[[File:2019-07-20 10 25 57 View south along Interstate 45 (North Freeway) from the ramp between westbound Interstate 10 and southbound Interstate 45 in Houston, Harris County, Texas.jpg|thumb|left|Southbound I-45 entering Downtown]]
Like the Gulf Freeway, the North Freeway soon became [[traffic congestion|congested]]. The [[oil boom]] of the 1970s resulted in large-scale [[residential development]] along the highway, most notably [[The Woodlands, Texas|The Woodlands]]. Since the corridor was strongly directional, with 65&nbsp;percent of peak-hour traffic going in the peak direction, a {{convert|9.6|mi|km|adj=on}} [[contraflow lane]] for [[bus]]ses and other [[HOV]]s was implemented later that decade, opening on August 28, 1979, between Downtown and Shepherd Drive (exit&nbsp;56B). The facility, operating during both [[rush-hour]] periods, occupied the leftmost lane of the other direction and was separated from the other lanes with a movable [[Traffic cone|pylon]] every {{convert|40|ft|m}}. In 1980, the existing center [[breakdown lane]]s were restriped for HOV traffic for about {{convert|2|mi|km|spell=in}} from the north end of the contraflow lane. Off-peak traffic, however, was increasing, and construction began in 1983 on a more permanent reversible transitway in the median. Thus, the second transitway in Houston (a month after the one on the [[Katy Freeway]]), opened on November 23, 1984, replacing the contraflow lane.<!--presumably ended at the slip ramp near Shepherd--><ref name=HF4/><ref name=HF6/>

Reconstruction of the mainlanes and frontage roads to handle increased traffic began in 1982 just north of Downtown. No lanes were added south of I-610, but the eight-lane cross-section, with room for a transitway, was continued north as construction progressed. Work was completed south of Airline Drive (exit&nbsp;53) in about 1985, to Shepherd Drive (exit&nbsp;56B) in 1987, and to [[Farm to Market Road 525|FM&nbsp;525]] (exit&nbsp;60A) in 1990; this last opening allowed the transitway to extend to just south of FM&nbsp;525. The [[Hardy Toll Road]], completed on June 28, 1988, between I-610 and I-45 near The Woodlands, added capacity to that part of the corridor, and, in 1990, reconstruction was completed on a short piece of I-45 from the toll road into The Woodlands. Reconstruction continued from FM&nbsp;525, reaching Airtex Boulevard (exit&nbsp;63) in 1997, including part of the [[Sam Houston Tollway]] interchange (completed in 2003) and a transitway extension, Cypresswood Drive (exit&nbsp;68) in 1998, extending the transit way to its present terminus, and the Hardy Toll Road (exit&nbsp;72) in 2003. Work on the section through The Woodlands to Research Forest Drive (exit&nbsp;77) was completed in 2001, including a direct connection to Woodlands Parkway<!--the southbound entrance opened later-->, and, in 2003, work was completed to [[Farm to Market Road 1488|FM&nbsp;1488]] (exit&nbsp;81).<ref name=HF4/> Construction is now complete between FM&nbsp;1488 to the [[Walker County, Texas|Walker County]] line near milepost&nbsp;100 just south of the northbound truck weigh station and [[New Waverly, Texas|New Waverly]], near [[Texas State Highway 75|SH&nbsp;75]] (exit&nbsp;98).<ref>{{cite news |first = Rad |last = Sallee |work = Houston Chronicle |url = http://www.chron.com/disp/story.mpl/metropolitan/moveit/3814116.html |title = Rail on Richmond idea first rejected back in '83 |archive-url = https://web.archive.org/web/20060610224215/http://www.chron.com/disp/story.mpl/metropolitan/moveit/3814116.html |archive-date = June 10, 2006 |date = April 23, 2006 }}</ref>

{{As of|2015}}, widening of the North Freeway from Downtown to the Sam Houston Tollway began. The plan for the project is to widen the freeway by adding managed lanes and adding the North Shepherd on- and offramps also known as [[Texas State Highway Spur 261|Spur&nbsp;261]] (which was already completed) prior to the I-45 widening project. This project has generated major controversy, with proponents claiming it would "enhance safety and mobility", while opponents point out that it would worsen air quality and greenhouse gas emissions, displace hundreds of people, and fail to meaningfully address congestion.<ref name=":1" /> 

Authorities in [[Harris County, Texas|Harris County]] have sued [[TxDOT]] to stop the expansion, and the federal government has investigated the expansion project to determine whether it violates any civil rights or environmental laws.<ref name=":0" /> Among others, the expansion has been opposed by U.S. Representative [[Sheila Jackson Lee]] and Harris County Judge [[Lina Hidalgo]].<ref>{{Cite news|last=Cerota|first=Andy|date=6 December 2021|title=Federal officials now investigating I-45 expansion project|url=https://www.click2houston.com/news/local/2021/12/06/federal-highway-administration-visits-houston-to-address-concerns-over-i-45-expansion-project/|access-date=December 18, 2021|archive-date=December 18, 2021|archive-url=https://web.archive.org/web/20211218182353/https://www.click2houston.com/news/local/2021/12/06/federal-highway-administration-visits-houston-to-address-concerns-over-i-45-expansion-project/|url-status=live}}</ref><ref>{{Cite web|last=Coalition|first=Make I.-45 Better|title=Make It Better|url=https://i-45coalition.org/documents|access-date=2021-12-18|website=Make I-45 Better Coalition|language=en-US|archive-date=December 18, 2021|archive-url=https://web.archive.org/web/20211218182355/https://i-45coalition.org/documents|url-status=live}}</ref> If completed, the highway's width will double to {{Convert|480|ft|m}}, wider than a football field. The highway expansion would displace around a thousand residents, including 919&nbsp;units in 16 apartment complexes, 160 single-family homes, five places of worship, and two schools.<ref name=":2" /> An apartment complex was acquired and vacated by TxDOT, which plans to demolish it for the expansion. TxDOT was heavily criticized for this planned demolition, as the apartment complex slated for demolition had been described as an example of good urban planning. <ref>{{Cite web |last=Jordan |first=Jay R. |date=2022-06-21 |title=TxDOT to tear down apartments for controversial I-45 expansion near downtown Houston |url=https://www.chron.com/news/houston-texas/transportation/article/TxDOT-to-demolish-apartments-to-make-way-for-17255413.php |access-date=2022-06-21 |website=Chron |language=en-US |archive-date=June 21, 2022 |archive-url=https://web.archive.org/web/20220621204935/https://www.chron.com/news/houston-texas/transportation/article/TxDOT-to-demolish-apartments-to-make-way-for-17255413.php |url-status=live }}</ref>

Parts of the freeway are paralleled by the [[METRORail Red Line]].<ref>{{Cite web|title=Houston · Texas|url=https://www.google.com/maps/place/Houston,+TX/@29.7909213,-95.3787253,12.83z/data=!4m5!3m4!1s0x8640b8b4488d8501:0xca0d02def365053b!8m2!3d29.7604267!4d-95.3698028!5m1!1e2|access-date=2021-12-18|website=Houston · Texas|language=en|archive-date=December 18, 2021|archive-url=https://web.archive.org/web/20211218182352/https://www.google.com/maps/place/Houston,+TX/@29.7909213,-95.3787253,12.83z/data=!4m5!3m4!1s0x8640b8b4488d8501:0xca0d02def365053b!8m2!3d29.7604267!4d-95.3698028!5m1!1e2|url-status=live}}</ref>

===Between Conroe and Richland===
The first part of I-45 between [[Conroe, Texas|Conroe]] and [[Richland, Texas|Richland]] was the bypass around [[Huntsville, Texas|Huntsville]].{{cn|date=October 2024}}

The final piece of I-45 between the cities opened on October 13, 1971, for {{convert|12|mi|km}} between [[Fairfield, Texas|Fairfield]]<!--which exit?--> and [[Streetman, Texas|Streetman]]<!--which exit?-->.<ref name=FHWA/>

===Richland to Dallas (Julius Schepps Freeway)===
The [[Central Expressway (Dallas)|Central Expressway]] was the first [[freeway]] in [[Dallas]], built as a new alignment of US&nbsp;75. It first opened between San Jacinto Street and Fitzhugh Avenue in 1949 and soon stretched south to [[Hutchins, Texas|Hutchins]]. The stretch through downtown, however, ran along the surface, as did the part south of the bridge over the [[Trinity River (Texas)|Trinity River]], due to diversion of funds to the north portion.<ref name=greenargon>{{cite web |url = http://www.greenargon.com/uh/uhprofile.php?id=39 |title = Urban History: Central Expressway |access-date = |archive-url = https://web.archive.org/web/20111001213013/http://www.greenargon.com/uh/uhprofile.php?id=39 |archive-date = October 1, 2011 }}</ref><!--should be replaced with a more reliable source--> By the late 1950s, a bypass to the east of the downtown section was planned.<ref>{{cite news |work = [[Dallas Times Herald]] |title = City Seeks Freeway Project |date = June 22, 1958 }}{{full citation needed|date=April 2020}}</ref> By the time construction reached Hutchins, in about 1955, the state decided to build further segments to full freeway standards. By 1961, the freeway was complete between Hutchins and the [[Texas State Highway 14|SH&nbsp;14]] split at [[Richland, Texas|Richland]], except for the bypass around [[Corsicana, Texas|Corsicana]], which was built {{Circa|1964}}.<ref name="NBI" /><ref name=Texas-1961>{{cite map |author = General Drafting Company |url = http://www.aaroads.com/texas/maps/1961-enco.html |title = Texas |archive-url = https://web.archive.org/web/20131203012144/http://www.aaroads.com/texas/maps/1961-enco.html |archive-date = December 3, 2013 |year = 1961 |publisher = Humble Oil }}</ref> This freeway was mostly built along the existing US&nbsp;75; one of the projects<!--exactly which?--> in [[Navarro County, Texas|Navarro County]], near Corsicana, was the first Interstate project in Texas approved under the [[Federal-Aid Highway Act of 1956]].<ref name=FHWA>{{cite web |author = Federal Highway Administration |url = https://highways.dot.gov/highway-history/interstate-system/50th-anniversary |title = Previous Interstate Facts of the Day |archive-url = https://web.archive.org/web/20060426084506/http://www.fhwa.dot.gov/interstate/previousfacts.cfm |archive-date = April 26, 2006 |publisher = Federal Highway Administration |url-status = live |access-date = }}</ref>

[[Image:Dallas, Texas 1955 Yellow Book.jpg|thumb|1955 "[[General Location of National System of Interstate Highways|Yellow Book]]" plan for Interstates in Dallas]]
It was not until 1964 that I-345, extending I-45 north along the proposed Central Expressway bypass, was added as a proposed state highway.<ref name=HDF-IH-345>{{TxDOT|IH|345|link=no}}</ref> I-45 and I-345 were built and opened in the 1970s, with the final section, between Lamar Street (exit&nbsp;283A) and the Central Expressway (exit&nbsp;283B),<ref name=NBI/> opening on February 25, 1976.<ref>{{cite news |work = [[The Dallas Morning News]] |title =  Interstate 45 to Open Feb 25 |date = February 15, 1976 }}{{full citation needed|date=April 2020}}</ref> At the north end, before it merged into the Central Expressway (which continued to carry US&nbsp;75), I-345 straddled the bridges over Bryan Street and Ross Avenue, the latter the location of the opening ceremonies in 1949.<ref>{{cite news |work = The Dallas Morning News |title = North Central Turns 35 Today |date = August 19, 1984 }}{{full citation needed|date=April 2020}}</ref> Because of their location, these two bridges were not replaced in the 1990s reconstruction of the North Central Expressway and are the only surviving grade separations from the initial construction north from downtown.<ref name=NBI>{{cite book |author = Federal Highway Administration |title = [[National Bridge Inventory]] |year = 2006 }}{{full citation needed|date=April 2020}}</ref>

At the time the interchange with I-20 was built, the freeway that crossed I-45 was then a part of [[Interstate 635 (Texas)|I-635]]; it would not be until later when, initially, I-20 was added to I-635 as a multiplex, then later still, I-635 would be truncated away from the I-45 interchange (back around to just north of what is now I-20's interchange with US&nbsp;175).<ref>{{TxDOT|IH|20|access-date = July 21, 2010|link = no}}</ref><ref>{{TxDOT|IH|635|access-date = July 21, 2010|link = no}}</ref>

Reconstruction and widening to six lanes, from the [[Ellis County, Texas|Ellis]]–[[Navarro County, Texas|Navarro]] county line (between exits&nbsp;243 and 244) north to [[Texas State Highway 310|SH&nbsp;310]] (exit&nbsp;275), began in 1991.<ref>{{cite news |first = Tony |last = Hartzel |work = [[The Dallas Morning News]] |title = Road to Better Driving |date = October 29, 2000 }}{{page needed|date=April 2020}}</ref> The last section, near the north end, was completed in 2002.{{Citation needed|date=August 2007}}
{{clear}}